US4270882A - Molecular pump or, respectively, gas-tight sealing arrangement for a body placed in a housing and rapidly rotating about an axis - Google Patents

Molecular pump or, respectively, gas-tight sealing arrangement for a body placed in a housing and rapidly rotating about an axis Download PDF

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Publication number
US4270882A
US4270882A US05/860,777 US86077777A US4270882A US 4270882 A US4270882 A US 4270882A US 86077777 A US86077777 A US 86077777A US 4270882 A US4270882 A US 4270882A
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US
United States
Prior art keywords
housing
sealing assembly
gap
groove
axis
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/860,777
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English (en)
Inventor
Waltherus J. Th. H. Luijten
Joost Smid
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ultra Centrifuge Nederland NV
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Ultra Centrifuge Nederland NV
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Filing date
Publication date
Application filed by Ultra Centrifuge Nederland NV filed Critical Ultra Centrifuge Nederland NV
Assigned to ULTRA-CENTRIFUGE NEDERLAND N.V. reassignment ULTRA-CENTRIFUGE NEDERLAND N.V. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: LUIJTEN WALTHERUS J. TH. H., SMID, JOOST
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/02—Multi-stage pumps
    • F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
    • F04D19/044—Holweck-type pumps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B5/00—Other centrifuges
    • B04B5/08—Centrifuges for separating predominantly gaseous mixtures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B7/00—Elements of centrifuges
    • B04B7/02—Casings; Lids

Definitions

  • the invention relates to a molecular pump or, respectively, a gas-tight sealing arrangement for a body--hereafter called rotor--placed in a housing and rapidly rotating about an axis, which sealing arrangement is mounted in this casing or, respectively, in a wall thereof, said sealing arrangement consisting of a stationary bush wall portion and an opposite moving bush wall portion of the body which is in the form of a body of rotation bounded on the outside by a generated surface so that there is at least one sealing gap between these wall portions, where at least one of these wall portions is provided with at least one salient helical resp. spiral dam which with the other wall portion bounds at least one continuous screw- or spiral thread.
  • Such a device is known, for example, from U.S. Pat. No. 2,730,297.
  • a very high speed of rotation is here intended to mean a speed in excess of the critical speed of the rotor.
  • the vibrations which occur while this critical speed is passed and the accompanying high bearing losses appear to form an obstacle.
  • these difficulties are met by supporting the rotor elastically so that it can work supercritically and besides adjust itself so that its centre of gravity coincides with the axis of rotation. The latter adjustment is possible without trouble if the support is made sufficiently elastic. Since during operation at speeds above critical the centre of gravity comes to lie as of itself in the axis of rotation, the bearing reactions become much smaller and ultimately disappear altogether. This ensures not only a very quiet running, but the bearing loss is also reduced to a minimum.
  • the rotor can be supported elastically by providing it with thin and flexible axle journals. It is also possible to use a magnetic support.
  • the relation between the dam section measured in the circumferential direction and the groove section also measured in the circumferential direction is made, according to the invention, smaller than 0.6 but larger than 0.3.
  • the angle between a tangent to the helical dam and a plane normal to the axis is made to be smaller than 0.20 but larger than 0.05, expressed in radians.
  • FIG. 1 is a vertical cross section of a molecular pump with the invention applied
  • FIG. 2 is a detailed illustration of a developed portion of the housing wall cut in the circumferential direction
  • FIG. 3 is an external view of a developed wall portion provided with helical channels.
  • the molecular pump illustrated in FIG. 1 is provided with a housing 1 in which a rotor 2 is placed. This is supported via a footstep 3, terminating in a footstep ball 4, in a footstep bearing 5 which is flexibly attached to a thin rod clamped in the bottom 7 of the housing 1. Because the rod 6 is thin it is capable of permitting radial deflections where, however, the centre position is always sought again owing to the elasticity of rod 6.
  • the rotor 2 is provided on top with a bore 3 in which, in the embodiment shown, a rod-shaped magnet 8 is secured. Opposite this magnet 8 there is a stationary magnet 9 mounted so that unlike poles of these magnets face one another and the magnets thus attract each other.
  • Magnet 9 is mounted inside a tube 10 which is fixed in the suction opening 12 of the pump by means of thin spokes 11.
  • the rotor 2 is fitted on its lower side with a cylindrical sleeve 13 which serves as the rotor of an electric motor and is driven by a stator 14.
  • This stator is secured to a partition 15 mounted in the lower part of the housing 1.
  • the inside of the cylindrical wall of housing 1 is fitted with a screw thread 16 which cooperates with the cylindrical wall 17 of rotor 2.
  • the partition 15 is provided with an outlet duct 20 which discharges the gas compressed by the pump.
  • FIG. 2 represents a magnified view of part of the screw thread unwound into a plane, with the wall 17 lying opposite.
  • This figure shows that the dimension of a screw thread, measured in the circumferential direction, is a 1 , whereas the dimension of a dam 18, also measured in the circumferential direction, is a 2 .
  • the height of such a dam is H o
  • the width of the gap measured between the wall 17 and the outermost part of a dam 18 is ⁇ R.
  • ⁇ R here represents the radial clearance between the rotor and the dams of the molecular pump or, respectively, the sealing.
  • H o is the radial depth of a screw thread.
  • FIG. 3 should hardly need any explanation.
  • the velocity vector 19 is also shown, representing the direction and magnitude of the velocity at which the wall 17 moves along the grooves and dams.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Positive Displacement Air Blowers (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
US05/860,777 1977-02-25 1977-12-15 Molecular pump or, respectively, gas-tight sealing arrangement for a body placed in a housing and rapidly rotating about an axis Expired - Lifetime US4270882A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NLAANVRAGE7702017,A NL184487C (nl) 1977-02-25 1977-02-25 Moleculaire pomp.
NL7702017 1977-02-25

Publications (1)

Publication Number Publication Date
US4270882A true US4270882A (en) 1981-06-02

Family

ID=19828052

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/860,777 Expired - Lifetime US4270882A (en) 1977-02-25 1977-12-15 Molecular pump or, respectively, gas-tight sealing arrangement for a body placed in a housing and rapidly rotating about an axis

Country Status (6)

Country Link
US (1) US4270882A (es)
AU (1) AU516159B2 (es)
BR (1) BR7801066A (es)
DE (1) DE2808125A1 (es)
GB (1) GB1588374A (es)
NL (1) NL184487C (es)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4732530A (en) * 1984-07-25 1988-03-22 Hitachi, Ltd. Turbomolecular pump
US4735550A (en) * 1985-07-31 1988-04-05 Hitachi, Ltd. Turbo molecular pump
US4746265A (en) * 1981-12-14 1988-05-24 Ultra-Centrifuge Nederland B.V. High-vacuum molecular pump
US4797062A (en) * 1984-03-24 1989-01-10 Leybold-Heraeus Gmbh Device for moving gas at subatmospheric pressure
US4806074A (en) * 1987-02-24 1989-02-21 Alcatel Hochvakuumtechnik Gmbh High-vacuum pump having a bell-shaped rotor
US5281086A (en) * 1991-09-11 1994-01-25 Andreas Stihl Pump for viscous fluids
US5380171A (en) * 1992-08-19 1995-01-10 Hitachi, Ltd. Turbo vacuum pump
US5501583A (en) * 1992-08-19 1996-03-26 Hitachi, Ltd. Turbo vacuum pump
US20040136846A1 (en) * 1999-06-23 2004-07-15 California Institute Of Technology Bladeless pump
CN110425286A (zh) * 2019-08-20 2019-11-08 葛亮 一种同轴双叶片气体隔离密封装置

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4579508A (en) * 1982-04-21 1986-04-01 Hitachi, Ltd. Turbomolecular pump
US4708586A (en) * 1985-08-14 1987-11-24 Rikagaku Kenkyusho Thread groove type vacuum pump
GB2200166B (en) * 1986-12-24 1991-08-14 Flux Geraete Gmbh Pump and method for the assembly thereof
JPH0686503A (ja) * 1992-09-03 1994-03-25 Hitachi Ltd モータ、ポリゴンミラーモータ、ディスク駆動モータ
CN2502048Y (zh) * 2001-09-20 2002-07-24 储琦 拖动分子泵

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2730297A (en) * 1950-04-12 1956-01-10 Hartford Nat Bank & Trust Co High-vacuum molecular pump
FR1265281A (fr) * 1960-05-18 1961-06-30 Rech S Electroniques Trilec So Dispositif pour produire un écoulement tourbillonnaire d'un fluide et applications de ce dispositif
US3071384A (en) * 1960-04-07 1963-01-01 Alsacienne Constr Meca Sealing structure for rotary mechanism
CH372521A (de) * 1961-08-14 1963-10-15 Landis & Gyr Ag Magnetisches Lager und Verfahren zu dessen Herstellung
US3131942A (en) * 1958-09-15 1964-05-05 Alsacienne Constr Meca Fluid-tight devices for rotating shafts
US3246901A (en) * 1963-04-02 1966-04-19 Du Pont Sealing arrangement for preventing escape of gas along a vertical rotating shaft
US3813134A (en) * 1971-06-25 1974-05-28 Reactor Ct Vibration dampers
US4002378A (en) * 1974-01-24 1977-01-11 Maschinenfabrik Augsburg-Nurnberg Ag Vertically supported rotary body
US4036565A (en) * 1974-09-27 1977-07-19 Balzers Patent Und Beteiligungs Ag Pump construction
US4116501A (en) * 1976-07-22 1978-09-26 Maschinenfabrik Augsburg-Nurnberg Aktiengesellschaft Cooling installation for the reduction of the oil temperature of oil-lubricated damping bearings

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL264293A (es) *
FR536278A (fr) * 1921-06-01 1922-04-29 Pompe hélicoïdale pour vides élevés
DE910204C (de) * 1950-04-12 1954-04-29 Philips Nv Hochvakuummolekularpumpe
US3066849A (en) * 1960-08-18 1962-12-04 Exemplar Inc High vacuum pump systems
US3150822A (en) * 1961-02-09 1964-09-29 Commissariat Energie Atomique Sealing and centering device for rotary shaft
FR1475765A (fr) * 1966-01-31 1967-04-07 Snecma Perfectionnements aux appareils à arbre vertical tournant à grande vitesse
DE1933031C3 (de) * 1969-06-30 1978-10-26 Karl 5170 Juelich Boden Magnetische Lagerung
NL160639C (nl) * 1969-07-22 1979-11-15 Tno Leger met een gegroefd loopvlak.
DE2052120A1 (de) * 1970-10-23 1972-04-27 Pfeiffer Vakuumtechnik Lageranordnung für Molekularpumpen und Turbomolekularpumpen

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2730297A (en) * 1950-04-12 1956-01-10 Hartford Nat Bank & Trust Co High-vacuum molecular pump
US3131942A (en) * 1958-09-15 1964-05-05 Alsacienne Constr Meca Fluid-tight devices for rotating shafts
US3071384A (en) * 1960-04-07 1963-01-01 Alsacienne Constr Meca Sealing structure for rotary mechanism
FR1265281A (fr) * 1960-05-18 1961-06-30 Rech S Electroniques Trilec So Dispositif pour produire un écoulement tourbillonnaire d'un fluide et applications de ce dispositif
CH372521A (de) * 1961-08-14 1963-10-15 Landis & Gyr Ag Magnetisches Lager und Verfahren zu dessen Herstellung
US3246901A (en) * 1963-04-02 1966-04-19 Du Pont Sealing arrangement for preventing escape of gas along a vertical rotating shaft
US3813134A (en) * 1971-06-25 1974-05-28 Reactor Ct Vibration dampers
US4002378A (en) * 1974-01-24 1977-01-11 Maschinenfabrik Augsburg-Nurnberg Ag Vertically supported rotary body
US4036565A (en) * 1974-09-27 1977-07-19 Balzers Patent Und Beteiligungs Ag Pump construction
US4116501A (en) * 1976-07-22 1978-09-26 Maschinenfabrik Augsburg-Nurnberg Aktiengesellschaft Cooling installation for the reduction of the oil temperature of oil-lubricated damping bearings

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4746265A (en) * 1981-12-14 1988-05-24 Ultra-Centrifuge Nederland B.V. High-vacuum molecular pump
US4797062A (en) * 1984-03-24 1989-01-10 Leybold-Heraeus Gmbh Device for moving gas at subatmospheric pressure
US4732530A (en) * 1984-07-25 1988-03-22 Hitachi, Ltd. Turbomolecular pump
US4735550A (en) * 1985-07-31 1988-04-05 Hitachi, Ltd. Turbo molecular pump
US4806074A (en) * 1987-02-24 1989-02-21 Alcatel Hochvakuumtechnik Gmbh High-vacuum pump having a bell-shaped rotor
US5281086A (en) * 1991-09-11 1994-01-25 Andreas Stihl Pump for viscous fluids
US5380171A (en) * 1992-08-19 1995-01-10 Hitachi, Ltd. Turbo vacuum pump
US5501583A (en) * 1992-08-19 1996-03-26 Hitachi, Ltd. Turbo vacuum pump
US20040136846A1 (en) * 1999-06-23 2004-07-15 California Institute Of Technology Bladeless pump
US7033132B2 (en) * 1999-06-23 2006-04-25 California Institute Of Technology Bladeless pump
CN110425286A (zh) * 2019-08-20 2019-11-08 葛亮 一种同轴双叶片气体隔离密封装置
CN110425286B (zh) * 2019-08-20 2020-07-03 乐清市芮易经济信息咨询有限公司 一种同轴双叶片气体隔离密封装置
CN111706529A (zh) * 2019-08-20 2020-09-25 刘小龙 一种同轴双叶片气体隔离密封装置
CN111706530A (zh) * 2019-08-20 2020-09-25 刘小龙 同轴双叶片气体隔离密封装置
CN111706529B (zh) * 2019-08-20 2021-06-29 苏州玛旭自动化科技有限公司 一种同轴双叶片气体隔离密封装置
CN111706530B (zh) * 2019-08-20 2021-06-29 苏州玛旭自动化科技有限公司 同轴双叶片气体隔离密封装置

Also Published As

Publication number Publication date
NL7702017A (nl) 1978-08-29
AU3273678A (en) 1979-08-02
NL184487B (nl) 1989-03-01
GB1588374A (en) 1981-04-23
AU516159B2 (en) 1981-05-21
NL184487C (nl) 1989-08-01
DE2808125C2 (es) 1987-02-19
DE2808125A1 (de) 1978-08-31
BR7801066A (pt) 1978-09-19

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